REVIEW | doi:10.20944/preprints201808.0170.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: evolution; development; physiology; structure
Online: 8 August 2018 (15:02:58 CEST)
That form and function relates, is the maxim to anatomy and physiology. Yet form-function relations can be difficult to establish. Human subjects with excessive trabeculated myocardium in the left ventricle, for example, are diagnosed with non-compaction cardiomyopathy, but the extent of trabeculations may be without relation to ejection fraction. Rather than rejecting a relation between form and function, we may ask whether the salient function is assessed; is there a relation to electrical propagation, mean arterial blood pressure, propensity to form blood clots, or all? And how should extent of trabeculated muscle be assessed? While reviewing literature on trabeculated muscle, we applied Tinbergen’s four types of causation - how does it work, why does it work, how is it made, and why did it evolve - to better parse what is meant by form and function. The paper is structured around cases that highlight advantages and pitfalls of applying Tinbergen’s questions. It further uses the evolution of lunglessness in amphibians to argue lung reduction can impact on chamber septation, and it considers the evolution of an arterial outflow in fishes to argue that reductions in energy consumption may drive structural changes with little consequences to function. Concerning trabeculations, we argue they relate to pump function in the embryo in the couple of weeks before the onset of coronary circulation. In fetal and postnatal stages, a spectrum of trabeculated-to-compact myocardium makes no difference to cardiac function and in this period form and function may appear unrelated.
REVIEW | doi:10.20944/preprints202003.0405.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: cancer; Cathepsin K; human; metastasis; physiology
Online: 27 March 2020 (10:33:50 CET)
The effect of proteolytic enzymes including Cathepsin K, a cysteine cathepsin, in onset and progression of cancers in human has been research intensive. Cathepsin K involves in many aspects and stages of cancers including apoptosis, cell proliferation, cancer immunology, inflammatory cell recruitment to tumors and aiding in the process of mobilization of normal healthy cells from their tissue compartments assisting in metastasis and angiogenesis. The objective of this review is to collect together and summarize and analyze the biochemical and physiological pathways of how cathepsin K is involved in onset and progression of cancers with more emphasis on breast and prostate cancers and cathepsin K regulated mechanisms underlying metastasis of such cancers to bones. Information for the review was gathered through published literature from global databases such as Google Scholar, PUBMED and NCBI on different studies on physiological interactions between enzymatic activity of cathepsin K with cancers and metastasis to bones. Analysis of published studies reveal that immunohistochemical studies of breast cancer cells indicate that they overexpress cathepsin K resulting in induction of aberrant mechanisms of cell signaling in breast cancers, creating a higher tendency for their metastasis to bones. Immunohistochemical, immunoprecipitation and fluorgenic assays of several studies done on the association of the same enzymatic activity on prostate cancers shows elevated levels of cathepsin K. Lesions derived from prostate cancer cell masses were observed to undergo increased bone formation and resorption levels. Such resorption levels cause secretion of biological factors promoting tumor expansion. In addition, studies indicate that Cathepsin K was observed to be a key component promoting higher bone resorption levels in patients suffering from cancer. Authors suggest that, to completely understand the association of cathepsin K on cancerous cells and their mechanism in metastasis, distributary patterns of cathepsin K in healthy human tissues needs to be extensively studied initially. It is also suggested that metastasis of breast and prostate cancers to bone could be terminated and overcome by successful production of efficient and precise inhibitory therapeutics targeting the enzymatic activity of Cathepsin K with minimum unintended adverse health effects.
REVIEW | doi:10.20944/preprints201903.0095.v1
Subject: Biology And Life Sciences, Biophysics Keywords: Striated Muscle, image reconstruction, muscle physiology
Online: 7 March 2019 (12:42:36 CET)
Much has been learned about the interaction between myosin and actin through biochemistry, in vitro motility assays and cryo-electron microscopy of F-actin decorated with myosin heads. Comparatively less is known about actin-myosin interactions within the filament lattice of muscle, where myosin heads function as independent force generators and thus most measurements report an average signal from multiple biochemical and mechanical states. All of the 3-D imaging by electron microscopy that has revealed the interplay of the regular array of actin subunits and myosin heads within the filament lattice has been accomplished using the flight muscle of the large waterbug Lethocerus sp. Lethocerus flight muscle possesses a particularly favorable filament arrangement that enables all the myosin cross-bridges contacting the actin filament to be visualized in a thin section. This review covers the history of this effort and the progress toward visualizing the complex set of conformational changes that myosin heads make when binding to actin in several static states as well as fast frozen actively contracting muscle. The efforts have revealed a consistent pattern of changes to the myosin head structures determined by X-ray crystallography needed to explain the structure of the different acto-myosin interactions observed in situ.
ARTICLE | doi:10.20944/preprints201802.0166.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: stand up paddle board; physiology; surfing
Online: 26 February 2018 (11:59:28 CET)
Stand Up Paddleboard (SUP) surfing entails riding breaking waves and maneuvering the board on the wave face in a similar manner to traditional surfing. Despite some scientific investigations on SUP, little is known about SUP surfing. The aim of this study was to investigate the physiological response during SUP surfing sessions and to determine how various environmental conditions can influence this response. Heart rate (HR) of an experienced male SUP surfer aged 43 was recorded for 14.9 hours during ten surfing session and synced with on board video footage to enable the examination of the effect of different surfing modes and weather conditions on exercise intensity. Results indicated the SUP surfer's HR was above 70% of HRmax during 85% of each session, with the greatest heart rates were found during falls off the board (~85%HRmax) and while paddling back to the peak (~83%HRmax). Total time surfing a wave was less than 5% with the majority of time spend paddling back into position. Wind speed positively correlated with HR (r2 = 0.062, p = 0.012) and wave height negatively correlated wave caching frequency (r2 = 0.54, p = 0.025). The results highlight the aerobic fitness for SUP surfing, that wave riding, paddling back to the peak and falls appear to be associated with the greatest cardiovascular demand and that environmental conditions can have an effect of physiological response during SUP surfing sessions.
REVIEW | doi:10.20944/preprints202310.0761.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: physiology; basketball; testing; explosive; unique; specific movements
Online: 12 October 2023 (05:32:49 CEST)
Basketball playing entails the repetitive performance of short intense actions using lower limb explosive power. As such, it is important to measure this capability in basketball players, especially among young players, and to optimize training programs and game plans. After presenting an in-depth understanding of the specific physiological requirements when playing basketball, as well as the type of movements required, The aim of this review is to better understand the importance of the physiological energy systems in basketball, to examine the contribution of each energy system and, accordingly, to heighten awareness of the importance and dominance of the alactic anaerobic physiological system in basketball, for actions requiring high level explosive power. This review of the literature depicts the horizontal and vertical physical movements and physiological requirements entailed in playing basketball, and presents eight standardized anaerobic alactic measurement tools relevant to the game. As some of these tests suit a number of ball games, the findings of this review article are important for making order of the elements unique to basketball as well as additional parameters to consider when testing basketball players. By reliably and validly testing the anaerobic alactic capabilities of basketball players, test results can be used for training purposes and for improving game outcomes. Despite the fact that much of the information in this review is familiar to coaches, highlighting the specific needs of basketball may help them to choose the most suitable tools, and may also shed light on new directions for developing basketball-specific assessment tests.
REVIEW | doi:10.20944/preprints202309.1841.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: tuberculosis; Mycobacterium; physiology; mycolic acids; cell wall
Online: 28 September 2023 (02:45:57 CEST)
Mycobacterium tuberculosis is the agent of tuberculosis, one of the most important infectious diseases in the world. This microorganism stands out from other bacteria, not only for its extremely high infection capacity, but also for its cellular characteristics that include an extremely resistant and hydrophobic cellular parade the passage of antibiotics. An incredible ability to adapt to adverse conditions inside the host as well as its vast arsenal of virulence factors that allow its survival within the inhospitable environment within the macrophage can be highlighted. This review aims to discuss several aspects of MTB microbiology, genetics, and physiology. We will address in this review details of the metabolism of MTB that allows it to replicate in the active phase and remain viable during latency, as well as the characteristics of its cell wall that contribute to the blockade of the immune response and its resistance to antibiotics.
ARTICLE | doi:10.20944/preprints202303.0251.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Asian rice; salt stress; morphology; physiology; biochemistry
Online: 14 March 2023 (06:51:35 CET)
Rice (Oryza sativa L.) is a primary energy food for Asian population. One of the most constraints in rice production is soil salinity because of the rice is very susceptible to salt. Meanwhile, many agricultural land in Asia are in the saline area. It is important to identify and develop salt-tolerant rice varieties that can adapt in Asian climate. By combining morphological, physiological, and biochemical assessments for screening the salt tolerant of 116 Asian rice cultivars was able to classify into tolerant, moderate, and sensitive rice cultivars under salinity stress condition, and also for understanding the salt tolerance mechanisms. The rice cultivars which belong to salt-tolerant including Pokkali from India, TCCP 266 from Philippines, IR 45427 also from Philippines, and Namyang 7 from Korea. Whereas, salt-sensitive rice varieties like IR29 from Philippines, IR58 also from Philippines, Daegudo from Korea, and Guweoldo also from Korea. The salt-tolerant varieties showed signs of tolerance, including lower percent reduction of percentage germination, root length, root fresh weight, shoot length, plant biomass, and chlorophyll content. In order to maintain the cellular osmotic balance under saline condition, the salt-tolerant ones exhibited less membrane damage, lower Na/K ratio, high proline and sugar accumulation, lower malondialdehyde (MDA) and hydrogen peroxide (H2O2). Pokkali from India, TCCP 266 from Philippines, IR 45427 also from Philippines, and Namyang 7 from Korea are recommended as valuable germplasm resource for Asian rice breeding program in saline agricultural area.
BRIEF REPORT | doi:10.20944/preprints202209.0340.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Locomotion; Motor Control; Muscle Synergies; Physiology; Running
Online: 22 September 2022 (10:30:24 CEST)
Instep weights cause mechanical changes, modifying muscle activity and changing ground plantar support. 30 semi-professional sprinters, randomized in 3 groups [no-weight, Ascending (50, 100, 150 and 200g), Descending (200, 150, 100 and 50g)] run 6 consecutive 50-meter series at maximum speed (first and sixth without weights); partial, total times and speed were analyzed. Instep weights were safe and well tolerated. 6th series speed decreased except in men’s ascending group, who achieved a lower time in sixth compared to first series. Weights presented in ascending order in men during warm-up could improve running time. Instep weights neuromuscular effects could compensate men’s tiredness in last series; weights could be included in training methodologies. Men training weights presented in ascending order may provide better results.
ARTICLE | doi:10.20944/preprints202012.0225.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Repeated Sprint Training; Speed Performance; Physiology; Sports
Online: 9 December 2020 (12:20:00 CET)
Background: Interventions with the performance of sessions with sprints in different intensity manipulations, can be a great alternative to improve physical performance. Objective: To verify the influence of different break times between sprints on the performance of amateur futsal athletes Methods: 10 individuals, men, amateur futsal athletes (Age: 21.5 ± 1.6; Weight: 72.4 ± 6.88; Height: 1.72 ± 0.05; BMI: 24.3 ± 1.2; Fat%: 13.7 ± 3.3, VO2peak: 49.1 ± 10.5) participated in the study. For the intervention, individuals were randomly selected to perform sessions with sprints (10 sets 20 meters) with different pause times, being 15 (S15), 30 (S30) and 60 (S60) seconds. For performance analysis, the speed (km / h) applied to each sprint was used, monitored by a device with a photocell (CEFISE Biotecnologia Esportiva®, Nova Odessa, São Paulo) and the statistical treatment of all data was through the software Statistica 7.0 (Statsoft ™, Tulsa, OK, USA) using a significance level of p≤0.05. Results: There was an interaction between speed and interval time (p = 0.000). For condition S15, a greater reduction in performance was observed (p≤0.05), while for S30 and S60, no significant reduction in performance was observed (p> 0.05). The data for the area under the curve showed a significant difference (p = 0.000), where the interval of 60 seconds (S60) was longer compared to the values of 30 (S30) (p = 0.000) and 15 seconds (S15) (p = 0.000). However, there were no significant differences between the 30 and 15 second data (p = 0.248). Conclusion: Shorter time (15 seconds) of interval between repeated sprints can significantly affect performance when compared to longer breaks (30 and 60 seconds). But, all the conditions tested here, can be positive for the improvement of the performance, mainly in sports that demand fast and efficient motor actions, as for example, futsal.
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: mechanistic; hypothesis; physiology; biology; pharmaceutical; biomedicine; preclinical
Online: 20 September 2020 (15:01:28 CEST)
This two-part series describes how to test hypotheses on molecular mechanisms that underlie biological phenomena, using preclinical drug testing as a simplified example. While pursuing drug testing in preclinical research, it is important for students to understand the limitations of descriptive as well as mechanistic studies. The former does not identify any causal links between two or more variables; it identifies the presence or absence of correlations. The latter has caveats presented in Parts I and II of this series. Part II also describes how to test for a causal link between drug-induced activation of biological targets and therapeutic outcomes. Here, the mechanism of action of the drug is identified with pharmacological or genetic approaches that modify the expression/activity of the drug targets. Without interference with the proposed mechanism of action, a causal link between activation (or inhibition) of the target P and the therapeutic outcomes of drug D cannot be established. Using pharmacological agonists and antagonists, gene knockout and overexpression, or protein knockdown tools, designing a full-factorial three-way ANOVA forces the investigator to include the appropriate control groups, mitigating the risk of false positive or false negative conclusions. Upon completion of this series, the educator and student will have some of the tools in hand to design mechanistic studies and interpret various experimental outcomes, with knowledge of strengths and limitations of preclinical research.
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: mechanistic; hypothesis; physiology; biology; pharmaceutical; biomedicine; preclinical
Online: 20 September 2020 (15:00:30 CEST)
Many discoveries in the biological sciences have emerged from observational studies, but student researchers also need to learn how to design experiments that distinguish correlation from causation. For example, identifying the physiological mechanism of action of drugs with therapeutic potential requires the establishment of causal links. Only by specifically interfering with the purported mechanisms of action of a drug can the researcher determine how the drug “causes” its physiological effects. Typically, pharmacological or genetic approaches are employed to modify the expression and/or activity of the biological drug target or downstream pathways, to test if the salutary properties of the drug are thereby abolished. However, experimental techniques have caveats that tend to be underappreciated, particularly for the newer methods. In this two-part series, the caveats and strengths of mechanistic preclinical research are described, using the intuitive example of pharmaceutical drug testing in experimental models of human diseases. This series is not intended to tackle the perpetual clash between the frequentist approach to statistics and other schools of thought. Rather, Part I focuses on technical practicalities and common pitfalls of cellular and animal models designed for drug testing, and Part II describes in simple terms how to leverage a full-factorial three-way ANOVA, to test for causality in the link between drug-induced activation (or inhibition) of a biological target and therapeutic outcomes. Upon completion of this series, the student is expected to appreciate the strengths as well as limitations of mechanistic research and to avoid some of its pitfalls.
ARTICLE | doi:10.20944/preprints202309.0315.v1
Subject: Biology And Life Sciences, Forestry Keywords: amazon tree; growth; physiology; photoinhibition; plasticity; light levels
Online: 6 September 2023 (04:10:10 CEST)
Defining the best conditions for the initial development of native species is one of the significant challenges to forest production. Therefore, this study aimed to evaluate andiroba's physiological behavior and growth (Carapa guianensis Aubl.) seedlings at different shading levels. In a nursery seedling, C. guianensis seedlings grew on 0, 30, 50, and 70% shading, obtained with polyethylene screens. We measured at six plants per treatment. For the physiological data we measurement four times the total chlorophyll content, chlorophyll a/b ratio, maximum photochemical efficiency of photosystem II (Fv/Fm), maximum potential photosynthesis (A), stomatal conductance (gs), transpiration (E), intrinsic water use efficiency (WUEi), and carbon use efficiency (CUE), besides the growth parameters. While for growth rates parameters we developed six evaluation for as leaf area ratio (LAF), relative growth rates (RGR), and net assimilation rate (NAR). Chlorophyll content and Fv/Fm were inversely proportional to the light intensity. The other physiological and growth parameters showed better behavior in shaded environments, emphasizing the 50% treatment, with no significant difference between the 30% shading treatment. Therefore, the C. guianensis seedlings present growth plasticity under different shading levels, and we recommended producing seedlings at 50 or 30% shading.
ARTICLE | doi:10.20944/preprints202305.1041.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Microbial physiology; Quorum Sensing; Quorum Quenching; Pseudomonas aeruginosa
Online: 15 May 2023 (12:13:55 CEST)
After a time away from the classrooms and laboratories due to the global pandemic, the return to the teaching activities during the semester represented a challenge to both teachers and students. Our particular situation in a Microbial Physiology course was the necessity of imparting in a shorter time, laboratory practices that usually take longer. This article describes a two-week long laboratory exercise that covers several concepts in an interrelated way: conjugation as a gene transfer mechanism, regulation of microbial physiology, production of secondary metabolites, degradation of macromolecules and biofilm formation. Utilizing a Quorum Quenching (QQ) strategy, the Quorum Sensing (QS) system of Pseudomonas aeruginosa is first attenuated. Then, phenotypes regulated by QS are evidenced. QS is a regulatory mechanism of the microbial physiology that relays on signal molecules. QS is related in P. aeruginosa to several virulence factors, some of which are exploited in the laboratory practices presented in this work. QQ is phenomenon by which QS is interrupted or attenuated. We utilized a QQ approach based on the enzymatic degradation of the P. aeruginosa QS signals in order to put in evidence QS-regulated traits that are relevant for our Microbial Physiology course.
ARTICLE | doi:10.20944/preprints202105.0593.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Theobroma cacao; light; abiotic stress; physiology; plant nutrition
Online: 25 May 2021 (08:56:26 CEST)
Cacao is an understory plant cultivated under full-sun monocultures to multi-strata agroforestry systems, where cocoa trees are planted together with fruit, timber, firewood, and leguminous trees, or grown within thinned native forests. Under agroforestry systems of cultivation, cacao is subjected to excess shade due to high density of shade trees, and overgrown or unmanaged pruning of shade trees. Cacao is tolerant to shade, and the maximum photosynthetic rate occurs around irradiance of 400 μmol m−2 s−1 but excess shade reduces the irradiance further which is detrimental to photosynthesis and growth functions. Intra-specific variation is known to exist in cacao for the required saturation irradiance. A greenhouse study was implemented with 58 cacao genotypes selected from four geographically diverse groups: (i) wild cacao from river basins of the Peruvian Amazon, (PWC), (ii) Peruvian farmers’ collection (PFC), (iii) Brazilian cacao collection (BCC) and (iv) national and international cacao collections (NIC). All the cacao genotypes were subjected to 50% and 80% shade where photosynthetic photon flux density (PPFD) was 1000 and 400 μmol m-2 ּs-1 respectively. Intra-specific variations were observed for growth, physiological and nutritional traits, and tolerance to shade. Cacao genotypes tolerant to shade were: UNG-77 and UGU-130 from PWC; ICT-2173, ICT-2142, ICT-2172, ICT-1506, ICT-1087, and ICT-2171 from the PFC; PH-21, CA-14, PH-990 and PH-144 from BCC; and ICS-1, ICS-39, UF-613 and POUND-12 from NIC. Genotypes that tolerate excess shade might be useful plant types to maintain productivity and sustainability in agroforestry systems of cacao management.
ARTICLE | doi:10.20944/preprints202103.0374.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: cfDNA; next generation sequencing; full marathon; exercise; physiology
Online: 15 March 2021 (11:52:33 CET)
Plasma cell-free DNA (cfDNA) is frequently analyzed using liquid biopsy to investigate cancer markers. Accordingly, we hypothesized this concept could be applied to the field of exercise physiology. Here, we aimed to identify specific cfDNA (spcfDNA) sequences in the plasma of non-treated human participants using next generation sequencing (NGS) and to clearly define the dynamics regarding the amounts of spcfDNA-fragments upon extreme exercise, such as running a full marathon. NGS analysis was performed using cfDNA of pooled plasma collected from non-treated participants. We confirmed the TaqMan-qPCR assay had a high sensitivity and found the spcfDNA sequence abundance was 16,600-fold higher than a normal genomic region. We then used the TaqMan-qPCR assay to investigate the dynamics of the levels of spcfDNA-fragments upon running a full marathon. Quantities of the spcfDNA fragments were significantly increased post marathon. Furthermore, the amounts of spcfDNA fragments strongly correlated with the numbers of white blood cells and plasma myoglobin concentrations. These results suggest the spcfDNA fragments identified in this study were highly sensitive response markers to extreme physical stress. The findings of this study may provide new insights into exercise physiology and genome biology on the human.
REVIEW | doi:10.20944/preprints202009.0396.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Feeding behavior; Feeding habits; Physiology; Hexacorallia; Octocorallia; Ceriantharia
Online: 17 September 2020 (10:48:18 CEST)
In this study, we performed a bibliographical review examining the scientific literature on “feeding in Anthozoa” theme for the period from 1890 to 2019, using scientific databases (Google Scholar) supplemented with additional literature. This study categorized published scientific papers on this topic by decade of publication, target taxa, variability of species studied in each order and main themes studied. As a result, 153 studies were found, and based on their content, it was observed that within Anthozoa, there has been a concentration of feeding studies on species in the orders Actiniaria (Hexacorallia), Scleractinia (Hexacorallia), and Alcyonacea (Octocorallia). This indicates that the other remaining orders of the group have been comparatively neglected with regards to their feeding aspects. Therefore, as data on feeding in some groups of Anthozoa are scarce, studies need to be carried out to fill the gaps that permeate this important benthic group, in order to better understand their ecology.
ARTICLE | doi:10.20944/preprints202303.0101.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: Maximal isometric adaptive force; Holding capacity; Muscle stability; Neuromuscular functioning; Neuromuscular control; Motor control; Muscle spindle; Muscle physiology; Regulatory physiology
Online: 6 March 2023 (09:50:47 CET)
Adaptation to external forces relies on a well-functioning proprioceptive system including muscle spindle afferents. Muscle length-tension control in reaction to external forces is most important regarding the Adaptive Force (AF). This study investigated the effect of different procedures, which are assumed to influence the function of muscle spindles, on the AF. 19 elbow flexors of 12 healthy participants were assessed by an objectified manual muscle test (MMT) with different procedures: regular MMT, MMT after pre-contraction (self-estimated 20% MVIC) in lengthened position with passive return to test position (CL) and MMT after CL with a second pre-contraction in test position (CL-CT). During regular MMTs, muscles maintained their length up to 99.7±1.0% of the maximal AF (AFmax). After CL, muscles started to lengthen at 53.0±22.5% of AFmax. For CL-CT, muscles were again able to maintain the isometric position up to 98.3±5.5% of AFmax. AFisomax differed highly significantly between CL vs. CL-CT and regular MMT. CL is assumed to generate a slack of muscle spindles which led to a substantial reduction of the holding capacity. This was immediately erased by a pre-contraction in test position. The results substantiate that muscle spindle sensitivity seems to play an important role for neuromuscular functioning and musculoskeletal stability.
ARTICLE | doi:10.20944/preprints202308.1908.v1
Subject: Environmental And Earth Sciences, Pollution Keywords: Bio-magnification; Bio-accumulation; degassing; methyl-mercury; fish physiology
Online: 29 August 2023 (09:01:55 CEST)
Mercury toxicity significantly threatens aquatic ecosystems, particularly impacting fish populations and human well-being. This article exposes the effects of mercury contamination on aquatic life and their habitats. Mercury primarily originates from natural degassing and anthropogenic activities and accumulates in aquatic organisms, most notably in predatory fish, through bio-accumulation and bio-magnification. This bio-accumulation, driven by microbial transformation to methyl-mercury, leads to elevated concentrations in top-level predators. The consequences of mercury exposure on fish physiology are stunted growth, reproductive impairments, and compromised immunity, with potential ramifications for population dynamics and ecosystem resilience. This study delves into specific impacts of mercury on fish, ranging from bone deformities to liver damage, developmental anomalies, neurotoxic effects, and disruptions in reproductive systems. The interplay between ecological, physiological, and human health effects underscores the need for a comprehensive understanding of mercury's underlying mechanisms. Monitoring mercury levels in aquatic systems emerges as a crucial strategy for ensuring fish populations' health and ecosystems' sustainability. Urgent collaborative efforts are imperative to address this global concern, promote harmonious coexistence between human activities and aquatic environments, and secure the availability of safe and nutritious fish for future generations. In conclusion, this article highlights the urgent necessity for targeted interventions and informed decision-making to mitigate the influence of mercury contamination on aquatic ecosystems.
ARTICLE | doi:10.20944/preprints202308.0041.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: entropy generation; control; elasticities; flow; optimality; physiology; biology; thermodynamics
Online: 1 August 2023 (10:41:02 CEST)
Living beings are composite thermodynamic systems in non-equilibrium conditions. Within this context, there are a number of thermodynamic potential differences (forces) between them and the surroundings, as well as internally. These forces lead to flows, which, ultimately, are essential to life itself. Living beings are under the pressures of natural selection, thus are biological flows as well. At the same time, the maintenance of homeostatic conditions, the tenet of physiology, demands regulation of these flows by control of variables. However, due to the very nature of these systems, regulation of flows and control of variables become entangled in closed loops. Therefore, the search for adaptation in flows takes a different path than the search for adaptation in morphological traits. Being at the roots of transfer processes, thermodynamic criteria turn out to be as natural physical candidates. Likewise, being at the roots of physiology, control turns out to be as a natural biological candidate in that path. Here we show how to combine entropy generation, with respect to a generalized process, and control of parameters (in such a generalized process) in order to create a criterium of optimal ways to regulate changes in generalized flows.
ARTICLE | doi:10.20944/preprints202305.0813.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Oryza sativa; restorer lines; physiology; nitrogen use efficiency; transcriptome
Online: 11 May 2023 (07:23:03 CEST)
Improving plant nitrogen use efficiency (NUE) is important for many crops, especially in hybrid breeding. Reducing nitrogen inputs is key for achieving sustainable rice production and decreasing environmental problems. Here, we analyzed the transcriptomic and physiological changes in two indica restorer lines (Nanhui511 and Minghui23) under high (HN) and low nitrogen (LN) conditions. Nanhui511 (NH511) was more sensitive to different nitrogen supplies and exhibited higher nitrogen uptake and NUE under HN conditions by increasing lateral root and tiller numbers in the seedling and maturation stages, respectively. It also exhibited a lower survival rate than that of MH23 when planted in chlorate-containing hydroponic solution, indicating its high nitrogen uptake ability under different nitrogen supply conditions. When transferred from LN to HN conditions, NH511 had 2456 differentially expressed genes, whereas MH23 had only 266. Furthermore, genes related to nitrogen utilization showed differential expression in NH511 under HN conditions, while the opposite was observed in MH23. These results will help decrease certain limitations of hybrid rice breeding and provide novel data for high-NUE hybrid rice cultivation.
Subject: Medicine And Pharmacology, Psychiatry And Mental Health Keywords: deep sleep; slow-wave activity; evolution; comparative; physiology; homeostasis
Online: 2 August 2022 (04:46:33 CEST)
A modern definition of “deep sleep” is elusive despite being ubiquitously appreciated as an important physiological state supporting health and homeostasis. In modern times, human deep sleep is identified by specific bioelectric signatures in the electroencephalogram (EEG) emerging somewhere between periods of wakefulness. However, deep sleep has been used to describe states of quiescence well before the first electrical brain recordings in the late 1800s, highlighting its own evolution in both lay and medical literature. Furthermore, EEG states are not only ill-defined in most mammals outside of humans and laboratory rodents, but non-existent in some invertebrates. Given that all organisms rest and do so with seemingly well-defined utility, it remains a challenge linguistically, scientifically, and comparatively define what “deep sleep” means—or what it should—in a research context. Here, I explore standard definitions of deep sleep from a modern, comparative perspective, and discuss potential problems of using a strict and narrow definition of such a fleeting concept that has historically undergone significant updates. Finally, I suggest a path towards resolving inconsistencies around the meaning of “deep sleep” and consider whether it is truly reflected by any one measure.
REVIEW | doi:10.20944/preprints202101.0630.v2
Subject: Social Sciences, Tourism, Leisure, Sport And Hospitality Keywords: tug of war; anthropometrics; physical capacities; physiology; injuries; kinetics.
Online: 14 September 2021 (11:34:06 CEST)
Tug-of-war (TOW) is an internationally played activity including professional and amateur athletes and defined as early (4000 years ago as a rope less version) in the artwork on Egyptian tomb engravings and is played as per the rules laid out by TWIF, which has 73 member countries and administrative headquarters in the USA. Typically, two teams of “pullers” participate and apply enormous contra directional forces on the pulling rope. Originally, two types of competition are used: knockout and points. This narrative review describes the scientific state of the art about of TOW. For the best of the author’s knowledge no previous information has been published. Anthropometric parameters are near 83.6, lean body mass 69.4, and body fat 16. The VO2MAX is 55.8 ml/kg/min. Relative strength, the dynamic leg power was 4659.8 N. Endurance TOW elicits minimal muscle damage. The injured strains and sprains comprised over half of all injuries: back (42%), shoulder–upper limb (23%) and knee (17%). Pulling movement in TOW contests can be divided into three phases: namely "Drop", "Hold" and "Drive" phase. The maximal pulling forces was 1041.6 ± 123.9 N. The percentage of dynamic pulling force in static maximal pulling force was 75.5 ± 14.4% and the dynamic ranged from 106.4 to 182.5%. There are two gripping styles, indoor and outdoor. The friction characteristics between surface and shoe in TOW is important to determine a suitable shoe for indoor TOW. Waist Belt might be a useful piece of equipment for TOW sport. The EMG technique in Tow described a high activity of dorsal muscle during the pulling. The factor of force vanishing was the coordination among athletes. The force vanishing percentage goes from 8.82±5.59 for 2 contenders to 19.74±2.22 for 8 athletes, 6.4 % in the sum of 2 pullers. However, in the drop phase, for female elite TOW team, only the 0.5 % of them pulling force was wasted. Future studies are need in order to understand better this historical sport activity.
ARTICLE | doi:10.20944/preprints202103.0223.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Abiotic Stress; Forestry; Tree Physiology; Plant Selection; Urban Forestry
Online: 8 March 2021 (13:42:34 CET)
Responses to water stress were measured for sugar maple (Acer saccharum subsp. saccharum Marshall) sources from Oklahoma (Caddo sugar maple), Missouri, Tennessee, Ontario and a black maple (Acer saccharum subsp. nigrum F. Michx.) source from Iowa. Seedling sources were selected for differences in temperature and precipitation of their geographic origins. Seedlings were preconditioned through moist (watered daily) or dry (watered every 4-7 days) cycles and then exposed to prolonged water stress. Dry preconditioned sugar maple seedlings from Oklahoma, Missouri, and Tennessee, sources from warmer and/or drier climates with greater relative evapotranspiration potentials, declined less rapidly in net photosynthesis, stomatal conductance, and water use efficiency (WUE) as water stress increased than dry preconditioned seedlings from Ontario and Iowa having origins in cooler, moister climates. Under imposed water stress the Ontario and Iowa sourced seedlings increased their root to shoot ratios and decreased their specific leaf area, mechanisms for drought avoidance. However, no corresponding changes in these values occurred for Oklahoma, Missouri, and Tennessee sources. Results from this study suggest greater tolerance of water stress in the Oklahoma, Missouri and Tennessee ecotypes from the western and southern range of sugar maple resulted primarily with WUE rather than other water stress coping mechanisms.
REVIEW | doi:10.20944/preprints202007.0417.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: adaptation physiology; sensors; precision livestock farming; wearable animal sensors
Online: 19 July 2020 (18:27:52 CEST)
Despite recent scientific advancements, there is a gap in the use of technology to measure signals, behaviors, and processes of adaptation physiology of farm animals. Sensors present exciting opportunities for sustained, real-time, non-intrusive measurement of farm animal behavioral, mental, and physiological parameters with the integration of nanotechnology and instrumentation. This paper critically reviews the sensing technology and sensor data-based models used to explore biological systems such as animal behavior, energy metabolism, epidemiology, immunity, health, and animal reproduction. The use of sensor technology to assess physiological parameters can provide tremendous benefits and tools to overcome and minimize production losses while making positive contributions to animal welfare. Of course, sensor technology is not free from challenges; these devices are at times highly sensitive and prone to damage from dirt, dust, sunlight, colour, fur, feathers, and environmental forces. Rural farmers unfamiliar with the technologies must be convinced and taught to use sensor-based technologies in farming and livestock management. While there is no doubt that demand will grow for non-invasive sensor-based technologies that require minimum contact with animals and can provide remote access to data, their true success lies in the acceptance of these technologies by the livestock industry.
ARTICLE | doi:10.20944/preprints202102.0440.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: warm up; muscle force; performance; resistance training; thermal imaging; physiology
Online: 19 February 2021 (14:15:20 CET)
(1) Background: The aim of the present study was to evaluate the effect of different types of warm-ups on the strength and skin temperature of Paralympic powerlifting athletes; (2) Methods: The participants were 15 male Paralympic powerlifting athletes. It was analyzed the effects of three different types of warm-up (without warm-up (WW), traditional warm-up (TW), or stretching warm-up (SW)) on static and dynamic strength tests as well as in the skin temperature, which was monitored by thermal imaging; (3) Results: show no differences in the dynamic and static indicators of the force in relation to the different types of warm-up. No significant differences were found in relation to the Peak Torque (p = 0.055, F=4.560, η2p= 0.246 medium effect), and 1-Repetition Maximum (p = 0.139, F=3.191, η2p = 0.186, medium effect) between the different types of warm-up. In the thermographic analysis, there was a significant difference only in the Pectoral muscle clavicular portion between the TW (33.04 ± 0.71ºC) and the WW (32.51 ± 0.74ºC) (p = 0.038). The TW method also presented slightly higher values than the SW and WW in the Pectoral Muscles Sternal portion and in the Deltoid anterior portion, but with p-value > 0.05; (4) Conclusions: that the types of warm-up studied do not seem to interfere with the performance of Paralympic Powerlifting athletes. However, the thermal images showed that traditional warm-up best meets the objectives expected for this preparation phase.
REVIEW | doi:10.20944/preprints202009.0040.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Coronaviruses; COVID-19; Pakistan; current situation; human physiology; diagnosis; treatment
Online: 2 September 2020 (09:59:45 CEST)
Coronavirus that is also known as COVID-19 disease is produced by SARSCoV-2. This causative agent is highly contagious and can cause potentially fatal pneumonia worldwide with serious public health concerns. In the beginning among infected individuals, most of them were those who were mainly shown to the wet animal market in a big city of China known as Wuhan. So, it was suggested that this was almost certainly the zoonotic source of COVID-19illness. The transitional source of origin and their mode of transmission to humans were not known obviously. Conversely, from human to human rapidly transformation have been confirmed generally. Currently, there is no availability of FDA approved clinically antiviral drugs and/or vaccines to be used against the COVID-19. Afterward, SARS-CoV and MERS-CoV, the occurrence of SARS-CoV-2 has been manifested as the third sketch of an enormously pathogenic coronavirus into human population globally. In this review, we provide a brief overview of the history of COVID-19 in Pakistan up-to 18th weeks after beginning, current situation, epidemiology, and its impact on the human population. Moreover, we focused on physiological variation during the incubation period, genome analysis of SARS-CoV2, supportive treatment approaches, and safety measures in the Pakistani population, which may be supportive for combating the risk of COVID-19 epidemic. We also reviewed the future approaches for the development of therapeutic interventions and vaccines to cope with the COVID-19 epidemic.
ARTICLE | doi:10.20944/preprints202008.0631.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Acidity attributes; fruit minerals; grapevine physiology; phenolic compounds; volatile compounds
Online: 28 August 2020 (10:20:31 CEST)
Kaolin protective effect was assessed in a white grapevine cultivar ‘Cerceal’ in ‘Alentejo’ Region (southeast Portugal) where plants face extreme conditions during summer season. We addressed the hypothesis that kaolin effects lead to several changes in leaves, fruits and wine characteristics on the primary and secondary metabolism. Results showed that kaolin reduces leaf temperature which provoke an improvement in physiological parameters such as net photosynthesis and water use efficiency. This protection interferes with berries colour, leaving them more yellowish, and an increase in phenolic compounds were observed in all fruit tissues (skin, seed and pulp). Also, both berry and wine characteristics were strongly affected, with an increase of tartaric and malic acid and consequently high total acidity, while the sugar concentration decreased 8.9% in berries provoking a low wine alcohol level. Results also showed that kaolin induces high potassium, magnesium and iron, and low copper and aluminum concentrations. Moreover, the control wine showed higher content of esters related with hostile notes whereas wine from kaolin treated vines presented higher content of esters associated with fruity notes. Overall, the results strengthen the promising nature of kaolin application as summer stress mitigation strategy protecting grapevine plants and improving fruits quality and more balanced wines.
ARTICLE | doi:10.20944/preprints202010.0102.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: lncRNA; LINC00961; SPAAR; scRNASeq; CRISPR/Cas9; cardiovascular physiology; fetal growth restriction; myocardial infarction
Online: 5 October 2020 (17:47:46 CEST)
Long non-coding RNAs (lncRNAs) have structural and functional roles in development and disease. We have previously shown that the LINC00961/SPAAR locus regulates endothelial cell function, and that both the lncRNA and micropeptide counter-regulate angiogenesis. To assess human cardiac cell SPAAR expression we mined a publicly available scRNSeq dataset and confirmed LINC00961 locus expression and hypoxic response in a murine endothelial cell line. We investigated post-natal growth and development, basal cardiac function, the cardiac functional response and tissue-specific response to myocardial infarction. To investigate the contribution of the LINC00961/SPAAR locus to determination of longitudinal growth, cardiac function, and response to myocardial infarction, we used a novel CRISPR/Cas9 locus knockout mouse line. Data mining suggested that SPAAR is predominantly expressed in human cardiac endothelial cells and fibroblasts, while murine LINC00961 expression is hypoxia-responsive in mouse endothelial cells. LINC00961-/- mice displayed a sex-specific delay in longitudinal growth and development, smaller left ventricular systolic and diastolic areas and volumes, and greater risk area following myocardial infarction compared with wildtype littermates. These data suggest a role for the LINC00961/SPAAR locus in cardiac endothelial cell and fibroblast cell function and hypoxic-response, and in growth and development, and basal cardiovascular function in adulthood.
ARTICLE | doi:10.20944/preprints201809.0455.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Flying-fox, disaster management, heat events, heat stress, roost management, physiology, veterinary management.
Online: 24 September 2018 (12:28:19 CEST)
Flying-fox populations are increasingly threatened by heat events, starvation events and other stressors due to habitat clearing and human/flying-fox conflict.These factors are unlikely to resolve, meaning that a well-coordinated and timely approach to flying-fox disasters is imperative for the mitigation of further flying-fox population impacts.
ARTICLE | doi:10.20944/preprints201806.0075.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: glaucoma; nitric oxide; spectral domain optical coherence tomography; aqueous humor outflow tract; physiology
Online: 6 June 2018 (06:09:24 CEST)
Purpose: To correlate outflow function and outflow tract vessel diameter changes induced by nitric oxide (NO). Methods: In a porcine anterior segment perfusion model, the effects of a nitric oxide donor (100 µM DETA-NO) on outflow facility were compared to controls (n=8 per group) with trabecular meshwork (TM) and after circumferential ab interno trabeculectomy (AIT). Outflow structures were assessed with spectral domain optical coherence tomography (SD-OCT) before and after NO, or an NO synthase inhibitor (100 µM L-NAME) and the vasoconstrictor, endothelin-1 (100 pg/mL ET-1). Scans were processed with a custom macro script and aligned for automated reslicing and quantification of cross-sectional outflow tract areas (CSA). Results: The facility increased after DETA-NO (0.189±0.081 μL/min·mmHg, p=0.034) and AIT (0.251±0.094 μL/min·mmHg, p=0.009), respectively. Even after AIT, DETA-NO increased the facility by 61.5% (0.190±0.074 μL/min·mmHg, p=0.023) and CSA by 13.9% (p<0.001). L-NAME + ET-1 decreased CSA by -8.6% (p<0.001). NO increased the diameter of focal constrictions 5.0±3.8 fold. Conclusions: NO can dilate vessels of the distal outflow tract and increase outflow facility in a TM-independent fashion. There are short, focally constricting vessel sections that display large diameter changes and may have a substantial impact on outflow.
ARTICLE | doi:10.20944/preprints202311.0336.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Poa crymophila; cold stresses; physiology; transcriptome analysis; weighted correlation network analysis (WGCNA); molecular mechanisms
Online: 6 November 2023 (10:33:41 CET)
Poa crymophila is a perennial, cold-tolerant, native grass species, widely distributed to the Qing-hai-Tibet Plateau. However, the molecular mechanism behind the cold stress tolerance and role of key regulatory genes and pathways of P. crymophila are poorly understood yet. Therefore, the present study investigated the physiological and transcriptome responses of P. crymophila’s roots, stems, and leaves under cold stress to explore the molecular mechanism of cold tolerance. Results of the present study suggested that cold stress significantly changed the physiologic characteristics of roots, stems, and leaves of P. crymophila. In addition, the transcriptome results showed that 4434, 8793, and 14942 differentially expressed genes (DEGs) were identified in roots, stems, and leaves, respectively; however, 464 DEGs were commonly identified in these three tissues. The Gene On-tology (GO) results showed that a large numbers of DEGs were significantly enriched in the pho-tosynthetic related categories in leaves. In addition, the “response to stimulus” category was sig-nificantly enriched in roots and stems. The Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that DEGs involved in “phenylpropanoid biosynthesis” were significantly enriched in roots, “photosynthesis” and “circadian rhythm-plant” pathways significantly enriched in stems and leaves, starch and sucrose metabolism, and galactose metabolism were pathways significantly enriched in three tissues. Weighted gene coexpression network analysis (WGCNA) identified Hub genes involved in P. crymophila cold response. This study provides new insights into the molecular mechanisms underlying the cold tolerance of P. crymophila belowground and aboveground tissues. In addition, specific genes involved in Ca2+ signaling, ROS scavenging system, hormones, circadian clock, photosynthesis, and transcription factors (TFs) were identified in P. crymophila. The identi-fication of key genes may provide valuable resources for further functional genomic and breeding studies.
REVIEW | doi:10.20944/preprints202308.1207.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: plant butenolides; karrikins; seed germination; plant ecology; crop physiology; plant development; swailing; vegetation restoration
Online: 17 August 2023 (03:13:14 CEST)
Fire-related cues could alter vegetation community composition by promoting or excluding different types of plants. Smoke-derived compounds have been a hot topic in plant and crop physiology. There are some fire-prone areas in Australia, both Americas, some Mediterranean countries and regions with extensive prescribed or illegal burning like central European, which are subjected to a direct impact of fire (heat, minerals accumulation from the burning matter) and/or the indirect one (smoke) and undergo compositional and structural changes. This review first updates information about the effect of the compounds on plants' kingdoms and focuses on the research advances in the field of smoke compounds and attempts to gather and summarize the recent state of research and opinions on the role of smoke-derived compounds in plants' lives. We finish our review by discussing major research gaps, which include: Why plants respond to smoke chemicals? Is the response of seeds to smoke and smoke compounds an evolutionary-driven trait allowing plants to adapt to local environment?
BRIEF REPORT | doi:10.20944/preprints202004.0043.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: lactation; physiology-based lactation models; drug exposure prediction; fasting; drug safety; newborn; infant; human milk
Online: 6 April 2020 (09:11:05 CEST)
There are guidelines on lactation following maternal analgo-sedative exposure, but these do not consider the effect of maternal fasting, nor fluid abstention on human milk macronutrient composition. We therefore performed a structured search (PubMed) on ‘human milk composition’ and screened title, abstract and full paper on ‘fasting’ or ‘abstention’ and ‘macronutrient composition’ (lactose, protein, fat, solids, triglycerides, cholesterol). This resulted in 6 papers and one abstract related to religious fasting (n=129 women) and observational studies in lactating women (n=23, healthy volunteers, fasting). These data reflect two different ‘fasting’ patterns: an acute (18-25h) model in 71 (healthy volunteers, Yom Kippur/Ninth of Av) women and a chronic fasting (Ramadan) model in 81 women. Changes were most related to electrolytes and were moderate, with almost no changes in macronutrients during acute fasting. We therefor conclude that neither short term fasting nor fluid abstention (18-25h) affect human milk macronutrient composition, so that women can be reassured when this topic were raised during consulting. Besides the nutritional relevance, this also matters as clinical research samples – especially to estimate analgo-sedative exposure by lactation - are commonly collected after maternal procedural sedation, associated with maternal fasting and physiology-based pharmacokinetic (PBPK) models assume stable human milk composition.
ARTICLE | doi:10.20944/preprints202309.0242.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: antioxidant capacity; glutathione; hydrogen peroxide; nitric oxide synthase; oxidative stress; su-peroxide ion; sperm physiology; reactive oxygen species
Online: 6 September 2023 (14:32:15 CEST)
Cryopreserved semen is widely used in Assisted Reproductive Technologies (ART) enabling the conservation and broad use of genetically superior semen. The quality of semen post-thawing determines the success of ART and despite the great advances in cryopreservation methods, the quality of frozen/thawed semen is still sub-optimal. Post-thawing spermatozoa endure oxidative stress (OS) due to the high levels of reactive oxygen and nitrogen species, which are produced during the freezing/thawing process, and the depletion of antioxidants. To counteract this depletion, supplementation of sperm preparation medium with antioxidants has been widely applied. Melatonin is a hormone with diverse biological roles and a potent antioxidant, with an ameliorative effect on spermatozoa. In the present study, the effect of melatonin on bovine spermatozoa was evaluated during in vitro sperm handling and under oxidative conditions in terms of sperm quality parameters and antioxidant capacity. Melatonin (100 μΜ) improved the kinematic parameters of spermatozoa, enhanced viability and reinforced the antioxidant status of spermatozoa by increasing cellular GSH levels and inhibiting iNOS protein expression.
REVIEW | doi:10.20944/preprints202310.0850.v1
Subject: Medicine And Pharmacology, Reproductive Medicine Keywords: sirtuin-1; SIRT1; sirtuins; human placenta; placental physiology; placental pathophysiology; preeclampsia; peroxisome proliferator-activated receptor γ; PPARγ; SIRT1/PPARγ signaling
Online: 13 October 2023 (07:58:19 CEST)
Sirtuins, especially SIRT1, play a significant role in the regulation of inflammatory response, autophagy, and cell response to oxidative stress. Since their discovery, sirtuins have been regarded as anti-aging and longevity-promoting enzymes. Sirtuin-regulated processes seem to take part in most prevalent placental pathologies, such as preeclampsia. Furthermore, more and more research studies indicate that SIRT1 may prevent pre-eclampsia development, or at least alleviate its manifestations. Having taken this into consideration, we have made a review of recent studies on the role of sirtuins, especially SIRT1, in the regulation of processes determining normal or abnormal development and functioning of the placenta.
CONCEPT PAPER | doi:10.20944/preprints202106.0486.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: high altitude, chronic hypobaric hypoxia, physiologic adaptation, travel to high altitude cities, high altitude physiology, pulmonary hypertension, lung disease, hemoglobin, tolerance to hypoxia, oxygen content.
Online: 18 June 2021 (15:22:04 CEST)
Acute high altitude illnesses are of great concern for physicians and people traveling to high altitude. High Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad which involves the Pneumo-Dynamic Pump (Ventilation), the Hemo-Dynamic Pump (Heart and circulation), and Hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The increased hemoglobin at high altitude reduces the percentage of dissolved oxygen in the arterial oxygen content with respect to sea level. At high altitude, the acid-base balance must be adequately interpreted using the high altitude Van-Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude the more tolerance to hypoxia. All organisms adapt physiologically and optimally to a high-altitude environment to survive. Reduction of pulmonary hypertension in HAPE through oxygen administration results in a favorable outcome.